Improving the resolution of Lazzaro winner-take-all circuit

Abstract

This paper describes an improvement on Lazzaro's winner-take-all (WTA) circuit (1989) which is one of the most widely used architectures among all CMOS WTA circuits. A salient drawback of the original circuit is its limited resolution which stems from low gain of its stages. Unlike previously reported improvements based on positive feedback, the output impedance of the current source providing the negative feedback have been increased by inserting a cascode connected transistor. Although very simple, this modification confers a significant resolution improvement on the circuit.